Psoriatic arthritis (PsA) is a chronic, debilitating inflammatory arthritis associated with psoriasis. Most studies to date include only patients with long standing disease. We know from rheumatoid arthritis, another type of inflammatory arthritis, that early identification and treatment initiation improves response to therapy and decreases joint damage and disability. It is possible that this is also the case in PsA, but to date, PsA is very difficult to identify early in the course of disease. Furthermore, very little is known about he earliest phases of PsA. As the majority of patients with PsA first develop psoriasis, patients with psoriasis represent an ideal population for studies investigating the development of PsA. In this application, we propose two approaches to detecting early disease: 1) to identify risk factors for development of PsA among patients with psoriasis, and 2) to identify subclinical articular and periarticular inflammation in patients with psoriasis, possibly the earliest form of the disease, using 18F-Flurorodeoxyglucose Positron Emission Tomography/Computed Tomography and musculoskeletal ultrasound. Not only will these studies address two potential approaches for identifying early disease, but through these innovative investigations we will gain insight into th natural history and pathophysiology of PsA development. The candidate is a rheumatologist and clinical investigator with an interest in inflammatory arthritis, particularly psoriatic arthriis, with a scientific background ideally suited for the K23 mentored career development award. Her goal is to become a successful, independently funded clinical investigator. Through the outlined career development plan and the proposed research, Dr. Ogdie will gain the required skills to achieve independence and to address her long-term objectives. The University of Pennsylvania is the ideal environment in which to conduct the proposed studies. Dr. Ogdie will leverage two existing R01 funded studies directed by the co-mentor to address the research Aims. With tremendous resources in rheumatology, dermatology, epidemiology, and radiology as well as outstanding mentorship, facilities, and equipment, Dr. Ogdie will build a strong foundation for career in patient-oriented clinical and translational investigation.